The focus of this conference will be on the development and evaluation of statistical and mathematical methods for use in research related to the analysis of data relating to the Acquired Immunodeficiency Syndrome (AIDS) epidemic with particular attention to issues associated with intravenous drug users. Among the topics to be addressed are: methods for projections of AIDS cases, mathematical models for the AIDS epidemic, natural history of HIV infection, and intervention studies and clinical trials. The goal of the conference is to bring together experts in several aspects of quantitative AIDS work -- statisticians, applied mathematicians and quantitative epidemiologists - in order to highlight and clarify important statistical issues in our understanding of the AIDS epidemic. A further goal will be to describe what are the key statistical and mathematical advances that are currently needed in each of the areas described above. Co-chairing this 1991 conference will be Dr. Nicholas P. Jewell of the University of California at Berkeley, Dr. Vern Farewell of the University of Waterloo, Canada, and Dr. Klaus Dietz of the University of Tubingen, Germany. Serving as Conference Director will be Dr. Donald L. Thomsen, Jr. (SIMS).